As a well-known copper-containing oxidase, tyrosinase has been anticipated to serve as the biomarker of skin diseases. We describe here an exquisite label-free fluorescent and colorimetric dual-readout assay of its activity, inspired by the specific oxidation ability of monophenolamine substrates to catecholamines and a unique fluorogenic reaction between resorcinol and catecholamines. By employing commercially available tyramine as the model substrate (dopamine as the product), it is found that the tyrosinase-incubated tyramine solution exhibits obvious pale yellow with intense blue fluorescence in the presence of resorcinol and O₂, where the absorbance and fluorescence intensity are directly related to the concentration of added tyrosinase (i.e., the amount of conversion of tyramine to dopamine). The overall process of sensing tyrosinase activity takes less than 100 min at ambient temperature and pressure conditions with exceedingly simple operation procedure, explicit response mechanism, and formation of fluorophore with high quantum yield from scratch. Furthermore, such a convenient, rapid, cost-effective, and highly sensitive dual-readout assay exhibits promising prospect for the tyrosinase activity in extensive bioassays and clinic research as well as in screening potential tyrosinase inhibitors.

中文翻译：

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酪氨酸酶活性双敏感检测的原位荧光和生色反应

酪氨酸酶作为一种众所周知的含铜氧化酶，有望成为皮肤疾病的生物标记。我们在这里描述了一种精美的无标记荧光和比色法双重读数测定法，其活性受到单酚胺底物对儿茶酚胺的特异性氧化能力以及间苯二酚和儿茶酚胺之间的独特荧光反应的启发。通过使用市售的酪胺作为模型底物（以多巴胺为产物），发现酪氨酸酶孵育的酪胺溶液在间苯二酚和O ₂的存在下呈现出明显的浅黄色和强烈的蓝色荧光。，其中吸光度和荧光强度与添加的酪氨酸酶的浓度（即，酪胺向多巴胺的转化量）直接相关。酪氨酸酶活性检测的整个过程在环境温度和压力条件下花费不到100分钟，操作过程极其简单，明确的响应机制以及从头开始形成具有高量子产率的荧光团。此外，这种方便，快速，具有成本效益和高度灵敏的双重读数测定法在广泛的生物测定和临床研究以及筛选潜在的酪氨酸酶抑制剂中显示出酪氨酸酶活性的有希望的前景。